Standard turbocharger as rocket turbopump?

[FourTee2]

After watching some videos and reading some articles about the Copenhagen Suborbitals, I've become inspired to someday build a largish liquid-propellant rocket engine. I just finished watching their video-presentation on the turbopump they are building for their TM65 engine, and it seems, well... large, heavy, and cumbersome. It then occurred to me that quite a few modern cars use a form of turbopump in their engines (a turbocharger) and I began to wonder if it would be possible to modify one of those for use in a rocket. People occasionally build jet engines out of them, so it doesn't seem *too* crazy of an idea. Frankly, I'm surprised that I can't find anything online about doing such a thing. In the Suborbitals' video, their engine designer states that their turbopump can move 18-20 liters of propellant per second, increasing its pressure to 18 bars. If one attached a high pressure steam source to the turbo's exhaust inlet and the air inlet of the cold side to the outlet of a propellant tank, would it be possible to achieve performance anywhere close to that?

The video I'm referencing:

[K^2]

A turbocharger is designed to force and compress an airflow. Turbopump pumps liquid fuel. The pump and the charger are going to be very different, because they are designed around very different densities. Now, the turbine stage of the turbocharger you might be able to reuse for a turbopump. It's going to be a matter of torque and RPMs you need for both, but you could probably find a pump that will work with what you have on the turbocharger's turbine output. Fortunately, finding a centrifugal pump that would work is much easier than finding a turbine. There are a number of centrifugal water pumps used for irrigation and what not designed to be driven directly by an electric motor. That means high RPM and low torque, which is what you have from the turbine. I'd check gardening and home improvement stores, then compare the specs you have on the turbocharger to these of the pump and try to find the best match.

It won't make a great turbopump, but as far as building something at home, that's probably your best bet. Of course, there's still the issue of driving the turbine, but that's a separate problem.

Honestly, for an early project, a turbopump is way overkill. If you don't have rocket-building experience, this is several levels of over your head. Start simple. I would recommend getting basics of solid fuel rocketry first. It's the sort of stuff that will explode but probably won't injure you unless you do something really stupid. Failures there will teach you how likely failures are and how to protect yourself from them. If and when you are ready to graduate to liquid fuels, again, start way simple. Build a pulse jet. Then try biprop rocket, but still just pressure-feeding the fuel and ox. Trust me, there are a lot of challenges just getting to such a stage. When you feel that you need more thrust than you can get with pressure-fed system, your first pump should be electric. Way, way safer and easier to scale.

Alternatively, if you really can't wait to make use of the turbines, you can try building a very basic turbojet out of a turbocharger using skills you learned building a pulse jet. Even here, I must stress, this shouldn't be your first project in propulsion.

Hopefully, this gives you some sort of idea of just how much you're jumping the gun here by trying to figure out turbopump first.

Edited February 18, 2014 by K^2

[Aghanim]

If you want to do a pulsejet, I suggest you go to this page: http://www.pulse-jets.com/valveless/

And choose your valveless design. I suggest you do Chinese CS because its everywhere on YT, but personally I think Messerschmitt design is cool because it integrates a ramjet into it, good for achieving supersonic speed

Use your browser search function

[Armchair Rocket Scientist]

What about a piston pump?

[Monroe Lee King Jr.]

I mentioned this on Arocket a couple years ago. Use a solid rocket motor (sugar and KNO3 is a good gas generator) to power your car turbocharger. Use a fluid coupling to your pump shaft (much like a car fan clutch) Because you cannot put a radial load on your turbine shaft. I figured a K impulse motor could make your turbine output 80 horsepower. I think it's a sound beginning for a turbopump

[Exosphere]

What about a piston pump?

Is there any information about how well that kind of pump scales to engine size? That's about a ten kN motor, which is both very small for commercial orbital (or even suborbital) uses, but extremely large for amateur biprop applications. Would that kind of design be feasibly scalable to a larger or smaller rocket?